Levels, Flavors, Options, Oh My! 

There are many approaches to open access, each with a name that may not have retained its original meaning, clouding discussions around OA. The distinction between green open access and gold open access, the two most common approaches, has not always been clear, as seen in this 2015 article about the advantages of each option. While the names for green and gold OA came from the Sherpa Romeo database, there are also less frequently used terms: 

Diamond/Platinum/Universal Open Access - where neither the reader nor the author have paid the publisher directly, either to access the article or through an Article Processing Charge. In this model, universities or other organizations have covered the costs assessed by the publisher. Although it is still not free to publish in this model, there are no costs to the end user. 

Bronze Open Access - when an article is published in a hybrid journal without any formal agreement or APC between the author and publisher to make it OA, but the article is made openly available after publication, that is bronze open access. This is a tenuous variety of open access, as the availability may change at any time, and the articles do not include an OA license allowing for reuse or redistribution. A 2018 study found that Bronze OA accounts for the majority of open access publishing. 

The gold and green open access models: 

Gold Open Access - PLOS ONE and all PLOS journals operate under the Gold Open Access model, charging authors fees to offset publishing costs (Article Processing Charges). 

• Hybrid - In practice, authors may face the choice of submitting their article to a journal that is partially closed, also called a hybrid journal. SAGE Publishing offers three models of open access publishing, including an option called "SAGE Choice", where authors may pay an APC (Article Processing Charge) to make their article open access in one of SAGE's traditional closed journals. 

Green Open Access - SAGE Publishing's green open access policy also allows authors to archive and post specific versions of their articles. Their policy is fairly standard among publishers, usually restricting authors to sharing the pre-print version of their article, and often setting an embargo period. Authors must wait until that embargo, usually 6-12 months after publication, has passed 

Green and Gold Open Access are two of the most common OA models - but what are the possibilities to completely change the economic model of scholarly publishing? 

• Collective funding
• Campus-based publishing
• Publishing cooperatives & collaborations
• Innovation

These definitions come from SPARC - read more about alternative publishing models, including their white paper "Income Models for Open Access: An Overview of Current Practice". 

If Gold and Green OA are popular, why is the economic model being reconsidered? 

• For-profit scholarly publishers are consolidated - the five largest publishers were responsible for publishing 50% of scholarly articles in 2013. 
• The profit margins of scholarly publishers are high - 36.8% profits were reported for 2017 by the parent company of Elsevier, the RELX Group, in their publishing division.
• Publishers provide a platform and infrastructure for publication and hosting of articles, and their editors contribute intellectual content by selecting and reviewing articles. But peer review is largely done by academics who are not paid by the publishers - that work is considered part of their service to their field. 
• Additionally, publishers have a double revenue stream from both paid access to read articles and paid APCs to publish articles. This double revenue stream, double dipping, explained: 

Gold Open Access shifts the costs of open access entirely to the author through an Article Processing Charge. However, with that APC assessed to the author, publishers are paid twice to publish that article - once by the author, and again by the subscribing institutions. Double dipping has been a driving force in many negotiations between universities and publishers, as in the University of California's 2019 broken big deal with Elsevier. 

Read more about double dipping: 

• This article from OpenAire discusses double dipping as a practice generally and specifically in regards to negotiations by scholarly organizations in the EU - those organizations have led changes in the OA movement, and leading funders like the European Commission will no longer reimburse authors' APCs in hybrid journals. 
• Joseph Esposito writes at the Scholarly Kitchen about possible OA models to remove double dipping. 
• Bernhard Mittermaier's 2015 article "Double dipping in hybrid open access - chimera or reality?" - Mittermaier surveyed 24 publishers and found that some level of double-dipping occurred at all of them, including those with "no double-dipping" policies. 

Green Open Access does not assess additional costs to read or publish, but is restrictive in keeping peer-reviewed versions of articles closed.